My main is a druid and I see a whole range of tips, today for instance I was tipped anywhere from 6pp to 50pp. On average I'd day people give between 15-25pp, but it fluctuates. In any case, don't sweat it too much. The most important thing is that you just say thanks or something.
[You must be logged in to view images. Log in or Register.] EQ is a social game and I get a lot of satisfaction out of making someone's EQ session just a little bit nicer.